Lift mechanism for dozer blade assembly



Dec- 14, 1965 B. A. Kum. 3,2%,4

LIFT MECHANISM FOR DOZER BLADE ASSEMBLY Filed Jan. 14, 1964 E Sheets-Sheet 1 4 j d@ Z INVENTOR.

Dec. 14, 1965 B. A. KUHL 3,222,804

LIFT MECHANISM FOR DOZER BLADE ASSEMBLY Filed Jan. 14, 1964 5 Sheets-Sheet 2 INVENTOR. 5mn/a //f/ Dec. 14, 1965 B. A. KUHL LIFT MECHANISM FOR DOZER BLADE ASSEMBLY 5 Sheets-Sheet 5 Filed Jan. 14. 1964 f l, l..

INVENTOR.

United States Patent O 3,222,804 LIFT MECHANISM FR DUZER BLADE ASSEMBLY Bernard A. Kahl, Lakewood, Uhio, assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed `Ian. 14, 1964, Ser. No. 337,591 4 Claims. (Cl. 257-144) This invention relates to a dozer assembly for a tractor and more particularly to an improved lift mechanism for raising and lowering the dozer blade.

It is quite common to have a dozer assembly in which push arms are pivotally connected to the tractor at one end and pivotally support a transverse dozer blade at the other end, together with adjustable tilt struts extending between each push arm and the dozer blade for til*- ing the latter about a transverse horizontal axis. Together with this type of arrangement, various types of lift mechanisms have been employed for raising and lowering the dozer blade about the pivotal connections between the push arms and vehicle. One difliculty with prior known lift mechanisms, however, has been that they -have not been capable of transmitting any loading along an axis extending longitudinally of the tractor such as is normally imposed on the dozer blade during a dozing operation. As a result, the push arms have served as the sole force-transmitting means of such loading thereby causing large stress concentrations in localized areas of the tractor.

One object of this invention is to provide a dozer blade lift mechanism that connects the central rear portion of the dozer blade with a forward portion of the tractor and serves as a force-transmitting means during a dozing operation.

Another object of this invention is to provide a tractor mounted dozer blade assembly having a lift mechanism that transmits forces from the dozer blade to the tractor during a dozing operation and permits the dozer blade to be rotated about an axis extending longitudinally of the tractor.

A further object of this invention is to provide a lift mechanism which connects the dozer blade with the front axle of a rubber-tired tractor in force-transmitting relationship and includes means for raising or lowering the dozer blade about a transverse pivot axis passing through the pivot connections between the dozer push arms and tractor.

In the preferred form, the above and other objects are realized with a dozer assembly having a pair of parallel push arms pivotally connected 'at/the rear ends thereof to the opposite sides of a rubber-tired tractor. An intermediate portion of each push arm supports an adjustable strut that extends forwardly for connection with an upper portion of a dozer blade which is pivotally supported at the forward ends of the push arms. A lift mechanism is located between the push arms for connecting the rear central portion of the dozer blade with the vehicle and comprises a pair of pivotally inter-connected members with the free ends thereof respectively connected to the dozer blade and the front axle of the tractor. An hydraulic lift cylinder is pivotally mounted to one of the members and extends upwardly for pivotal connection with the tractor so that during normal dozing operations a portion of the forces acting against the dozer blade are transmitted through the lift mechanism directly to the tractors axle to decrease the loading on the push arms and thereby eliminate large stress concentrations in any one part of the tractor.

A more complete understanding of this invention can be obtained from the following detailed description when read in conjunction with the accompanying drawings in which:

FIGURE l is an elevational view of a dozer assembly mounted on a rubber-tired tractor and incorporating a lift mechanism made in accordance with the invention;

FIGURE 2 is a plan View of the dozer assembly, lift mechanism, and tractor of FIGURE l;

FIGURE 3 is an enlarged sectional view taken on line 3-3 of FIGURE 2 and illustrates the location of the various components of the dozer assembly and lift mechanism when in the raised, lowered, and dozing positions;

FIGURE 4 is a front elevational view of the tractor of FIGURE 1 with portions broken away to reveal details of the dozer assembly and lift mechanism;

FIGURE 5 is a view similar to FIGURE 4 with parts broken away to show the positions of the various components of the dozer assembly and lift mechanism when the dozer blade is angled for ditching, side hill or gouging operations; and

FIGURE 6 is a side elevational view of the angled dozer blade assembly of FIGURE 5.

Referring now to the drawings and specifically FIG- URES l and 2, a rubber-tired vehicle or tractor 10 is shown mounting a dozer assembly l2 which incorporates a lift mechanism 14 made in accordance with the invention. In general, the tractor 10 is of the articulated type having front and rear frame sections 16 and 18 hinged together substantially midway between the front and rear wheels by vertically spaced and aligned pivot connections 20 and 22. The front frame section 16 is rigidly connected with a transverse axle 24 which rotatably supports the front wheels while the rear Wheels are carried by the rear axle (not shown) which is mounted to the frame section 18 for oscillation about an axis extending longitudinally of the vehicle. An operators station 26 is provided on the rear frame section forward of an engine compartment 28 and includes a steering wheel 30 which connects with appropriate valving for directing pressurized hydraulic Huid to a pair of double-acting hydraulic steering jacks 32 connected between the frame sections, as seen in FIGURE 2. Thus, rotation of the steering wheel causes one of the steering jacks to expand and the other to contract so that the frame sections move relative to each other about a vertical axis passing through the pivot connections 20 and 22. For a more complete description and disclosure of an articulated vehicle having a similar steering arrangement reference is made to Bernotas 2,981,356 granted April 25, 1961 to the assignee of this invention.

The dozer assembly l2 attached to the front frame section of the above-described vehicle comprises a pair of parallel beam-like push arms 34 and 36 located outboard of the front wheels and respectively attached at the rear thereof to transverse cone-shaped support bars 38 and 40 rigidly connected with and extending from opposite sides of the frame section 16. Each support bar terminates with a ball 42 that serves to universally pivotally support the rear of the associated push arm and permit movement thereof in a manner to be described. As best seen in FIGURES l and 3, a dozer blade 44 is mounted to the forward ends of the push arms 34 and 36 through pivot connections 46 and 47 respectively for pivotal movement about a transverse axis located forwardly of the front tires. Intermediate the ends of each push arm, a support bracket 48 is provided for pivotally carrying one end of a double-acting hydraulic tilt jack 50, the rod portion of which is pivotally connected at a point 52 to an upper portion of the dozer blade 44. The tilt jacks 5) serve as adjustable struts which serve to tilt the dozer blade fore and aft about a transverse axis passing through the pivot connections 46 and 47, and also serve to angle the dozer blade as will be described hereinafter.

The lift mechanism I4 employed with the abovedescribed dozer assembly is shown in detail in FIGURE 3 and extends between a central rear portion of the dozer blade 44 and the forward end of the vehicle 10. More specifically, and as seen in FIGURES 2 and 3, the lift mechanism comprises a bell crank member 54 having laterally spaced arms 56 and 5S, both of which are pivotally connected to the lower rear of the dozer blade through trunnions 60 which are axially aligned with the pivot connections 46 and 47. Midway between and to the rear of the arms 56 and 58, a spherical seating portion 62 is formed in the bell crank member for accommodating a ball 64 rigidly connected to a clevis member 66 which has the arms 68 and 70 thereof extending rearwardly for pivotal connection with the axle 24 at points 72 and 73 respectively. In addition, a double-acting hydraulic lift cylinder or jack 74 is provided with the rod portion 76 thereof pivotally connected to the bell crank at a point 78 while the cylinder portion 80 is housed in a universal coupling 82 supported by a bracket 84 extending upwardly from the front end of the vehicle. The universal coupling serves to allow movement of the lift cylinder 74 about mutually perpendicular pivot axes as defined by the trunnions 86 and 87.

Inasmuch as the lift cylinder 74 is double-acting, the dozer blade assembly can be moved under power either in the upward or downward direction from the full line position as viewed in FIG. 3. In this connection, it should be noted that when the lift cylinder is fully contracted the dozer blade assembly 12 is raised about a transverse horizontal axis passing through the balls 42 to the phantom line position indicated by the Roman numeral I. During such movement, the distance between the pivot point 72 and the trunnon 60 increases to compensate for the fact that the lift mechanism is pivoted to the vehicle about a transverse axis passing through the pivot point 72 while the push arms are mounted for pivotal movement about a transverse axis through ball 42. This increase in distance is possible due to the fact that the clevis member 66 is universally connected by the ball 64 to the bell crank member S4 at a point above a line passing through the trunnon 60 and pivot point 72. Thus, as the lift cylinder 74 is contracted to raise the dozer assembly from the full line position to position I, the bell crank member 54 rotates clockwise about the ball 64 and thereby causes the trunnion 60 to approach alignment with pivot point 72 and ball 64. In addition, it should be noted that when the lift cylinder is extended, the dozer blade moves to the position indicated by the Roman numeral II and, again as in a raising operation, the distance between the pivot connections 60 and 72 increases which is compensated for by the movement of the bell crank member 54 in a clockwise direction as in the above-described case.

One important feature of the lift mechanism described above, is that in the normal dozing position of the dozer assembly as indicated in full lines in FIG. 3, axial forces acting against the dozer blade serve to place the clevis member 66 in compression and the lift cylinder 74 in tension with the result that forces are transmitted to the vehicle through the lift mechanism as well as through the push arms 34 and 36 so as to prevent any severe stress concentrations in any one portion of the dozer assembly or vehicle. In explanation of this feature, it should be noted that when a force such as that indicated by the letter F is applied to the dozer blade, the horizontal component thereof acts through the trunnion 60 so as to provide a counterclockwise force couple about the center of the ball 64. This couple is resisted by the lift cylinder 74 so that the net result is that through the bell crank member 54, the clevis member is placed in compression and a portion of the loading on the dozer blade is transferred to the vehicle through the axle 24. Thus in effect, a rigid connection is provided between the central portion of the dozer blade 44 and the central forward portion of the vehicle while still permitting all of the desirable movements of the dozer blade required `for various dozing operations. In this regard, the dozer blade 44 can be tilted forwardly and rearwardly about the transverse pivot axis through the pivot connections 46 and 47 by concurrent expansion and contraction respectively of the tilt cylinders 50. In addition, the dozer blade can be angled for ditching, side hill and other operations by contracting one of the tilt cylinders while expanding the other, for example as seen in FIGURES 5 and 6. In this instance, the ball and socket connection betwen the bell crank member and clevis member serves as the pivot point about which the blade is rotated about an axis extending longitudinally of the vehicle.

Various changes and modifications can be made in my apparatus without departing from the spirit of the invention. It should be understood that these changes and modifications are contemplated and therefore I do not wish to be limited in any manner except as defined by the appended claims.

I claim:

1. In combination with a vehicle, a dozer assembly comprising a pair of push arms, means pivotally connecting one end of said push arms to said vehicle for rotation about a first transverse axis, a dozer blade extending transversely of said vehicle and mounted to the other end of said push arms for pivotal movement about a second transverse axis, a lift mechanism connected between said vehicle and said dozer blade, said lift mechanism comprising a first member connected to said dozer blade for pivotal movement about said second transverse axis, a second member connected to said vehicle for pivotal movement about a third transverse axis located forwardly of the first transverse axis, a ball and socket connection joining said first and second members at a point located between said dozer blade and said vehicle, a double acting duid-operated jack connected between said tirst member and said vehicle for raising and lowering said dozer blade about said first transverse axis and connected to said first member at a point forward of said ball and socket connection so that forces acting against said dozer blade during a normal dozing operation place the operating means in tension and the second member in compression so as to decrease the loading on the push arms, and adjustable strut means pivotally connected between each push arm and said dozer blade for pivoting the latter about said second transverse axis and about said ball and socket connection so that said blade can be rotated about the longitudinal axis of the vehicle.

2. In combination with a rubber-tired vehicle having a frame supporting a front wheel-carrying axle, a dozer assembly comprising a pair of push arms, means pivotally connecting one end of said push arms to said vehicle frame for rotation about a first transverse axis, a dozer blade extending transversely of said vehicle and mounted to the other end of said push arms for pivotal movement about a second transverse axis, a lift mechanism connected between said vehicle and said dozer blade, said lift mechanism comprising a first member connected to said dozer blade for pivotal movement about said second transverse axis, a second member connected to said axle for pivotal movement about a third transverse axis located between said first and second transverse axes, a ball and socket connection joining said lirst and second members at a point located between said dozer blade and said vehicle, operating means connected between said first member and said vehicle for raising and lowering said dozer blade and connected to said first member at a point forward of said ball and socket connection so that forces acting against said dozer blade during a normal dozing operation place the operating means in tension and the second member in compression so as to decrease the loading on thel push arms, and a uid-operated jack pivotally connected between each push arm and said dozer blade for tilting the latter about said second transverse axis and about said ball and socket connection so that said blade can be rotated about the longitudinal axis of the vehicle.

3. In combination with a vehicle, a dozer assembly comprising a pair of push arms, means pivotally connecting one end of said push arms to said vehicle for rotation about a rst transverse axis, a dozer blade extending transversely of said vehicle and mounted to the other end of said push arms for pivotal movement about a second transverse axis, a lift mechanism connected between said vehicle and said dozer blade, said lift mechanism comprising a bell crank member connected to said dozer blade for pivotal movement about said second transverse axis, a clevis member having the arms thereof connected to said vehicle for pivotal movement about a third transverse axis located forwardly of the iirst transverse axis, a ball and socket connection joining said bell crank and clevis members at a point located above a plane passing through said second and third transverse axes when said blade is in the lowered position, and a duid-operated jack connected between said bell crank member and said vehicle for raising and lowering said dozer blade, said jack connected to said bell crank at a point forward of said ball and socket connection so that forces acting against said dozer lblade during a normal dozing operation place the operating means in tension and the second member in compression so as to decrease the loading on the push arms, and Huid-operated jack means connected between each push arm and said dozer blade for tilting the latter about said second transverse axis and about said ball and socket connection so that said blade can be rotated about the longitudinal axis of the vehicle.

4. In combination with a rubber-tired vehicle having a frame supporting a front Wheel-carrying axle, a dozer assembly comprising a pair of `push arms pivotally connected at one end thereof to said frame, a dozer blade extending transversely of said vehicle and pivotally mounted vto the other end of said push arms for pivotal movement about a first transverse axis, a lift mechanism connected between said vehicle and said dozer blade, said lift mechanism comprising a first member connected to said dozer blade for pivotal movement about said first transverse axis, a second member connected to said front axle for pivotal movement about a second transverse axis, means universally pivotally interconnecting said first and second members at a point located to one side of a plane passing through said lirst and second axes when said blade is in a normal idozirrg position, rst operating means connected between said rst member and said vehicle for raising and lowering said dozer blade, second operating means connected to said dozer blade yfor selectively pivoting the latter about the first transverse axis and about said universal interconnection between said iirst and second members so that said blade can be rotated about the longitudinal laxis of the vehicle, said rst operating means connected to said rst member at a point so that a portion of the forces acting against said dozer blade during the normal dozing operation are transmitted to said Ifront axle so as to decrease the loading on the push arms.

References Cited by the Examiner UNITED STATES PATENTS 1,997,001 4/1935 Lamb 37--144 2,364,657 12/ 1944 Proctor et al. 37-144 2,624,131 1/ 1953 Rockwell 37-144 2,625,755 l/1953 Drott 37--144 2,899,760 8/1959 Armington et al 37-144 FOREIGN PATENTS 546,465 7/ 1942 Great Britain.

ABRAHAM G. STONE, Primary Examiner.

WILLIAM A. SMITH, III, Examiner. 

4. IN COMBINATION WITH A RUBBER-TIRED VEHICLE HAVING A FRAME SUPPORTING A FRONT WHEEL-CARRYING AXLE, A DOZER ASSEMBLY COMPRISING A PAIR OF PUSH ARMS PIVOTALLY CONNECTED AT ONE END THEREOF TO SAID FRAME, A DOZER BLADE EXTENDING TRANSVERSELY OF SAID VEHICLE AND PIVOTALLY MOUNTED TO THE OTHER END OF SAID PUSH ARMS FOR PIVOTAL MOVEMENT ABOUT A FIRST TRANSVERSE AXIS, A LIFT MECHANISM CONNECTED BETWEEN SAID VEHICLE AND SAID DOZER BLADE, SAID LIFT MECHANISM COMPRISING A FIRST MEMBER CONNECTED TO SAID DOZER BLADE FOR PIVOTAL MOVEMENT ABOUT SAID FIRST TRANSVERSE AXIS, A SECOND MEMBER CONNECTED TO SAID FRONT AXLE FOR PIVOTAL MOVEMENT ABOUT A SECOND TRANSVERSE AXIS, MEANS UNIVERSALLY PIVOTALLY INTERCONNECTING SAID FIRST AND SECOND MEMBERS AT A POINT LOCATED TO ONE SIDE OF A PLANE PASSING THROUGH SAID FIRST AND SECOND AXES WHEN SAID BLADE IS IN A NORMAL DOZING POSITION, FIRST OPERATING MEANS CONNECTED BETWEEN SAID FIRST MEMBER AND SAID VEHICLE FOR RAISING AND LOWERING SAID DOZER BLADE, SECOND OPERATING MEANS CONNECTED TO SAID DOZER BLADE FOR SELECTIVELY PIVOT- 